Question

The eye-lens can change its focal length by changing its thickness with the help of its muscles.

Answer 1

The ciliary muscle is an intrinsic eye muscle that is developed as a ring of smooth muscle in the central layer of the eye, called the uvea (vascular layer).

1. It regulates the flow of aqueous humor and governs accommodation for perceiving objects at different distances.
2. The choroid functions like a spring, tugging on the lens via the zonule fibers when the ciliary muscle is relaxed, causing the lens to flatten.
3. When the ciliary muscle contracts, the choroid extends, alleviating strain on the lens and causing the lens to thicken.